Copying apparatus having determination unit for special original and for controlling copying and marking based on determination

ABSTRACT

A copying apparatus includes an image reading unit for optically reading an original and for outputting image signals, an image processing unit for processing the image signals from the image reading unit in accordance with a predetermined method and for outputting image data, a printer unit for forming an image corresponding to the image data from the image processing unit on a recording sheet, a determination unit for determining whether the rank of certainty that the original is the same as the special original such as paper money is a first rank or a second rank, a control unit for prohibiting the image corresponding to the image data from being formed on the recording sheet when the determination result obtained by the determination unit is the first rank, and a marking unit for adding a predetermined mark on the recording sheet when the determination result obtained by the determination unit is the second rank.

TECHNICAL FIELD

The present invention relates to a copying apparatus having adetermination unit for determining whether or not an original to becopied is a special original, such as paper money and securities, whichare prohibited from being copied by law.

BACKGROUND ART

In recent years, due to improvement of an image processing technique andan image forming technique, a copy of paper money obtained by a colorcopy machine is so exquisite that it is difficult to distinguish thecopy from the actual paper money. Thus, a color copy machine has beenproposed, in which a special original such as the paper money, which isprohibited from being copied by law, is detected and a copy operationfor such a special original is prohibited from being carried out.

In an image recording apparatus disclosed, for example, in Japanese LaidOpen Patent Application No.2-83571, image data obtained by reading of anoriginal is compared with registered pattern data corresponding to aspecial original using a pattern matching method. It is then determinedbased on the comparison result whether or not the original is thespecial original (such as the paper money). When it is determined thatthe original is the special original, a copying operation for theoriginal is prohibited or an image (an all black image) different froman original image is formed on a paper.

However, since there are limitations of image reading accuracy and imageanalyzing accuracy, it is difficult to determine, at a accuracy of 100%,whether or not an original set on the copy machine is the specialoriginal. Thus, a degree to which an image obtained by reading theoriginal (an input image) is similar to the pattern data is evaluated asa similarity value. If the similarity value for the input image is equalto or greater than a predetermined reference similarity value, it isgenerally determined that the original to be copied is the specialoriginal.

In a case where it is determined, using the similarity value as has beendescribed above, whether or an original set on the copy machine is thespecial original, if the original is clearly seen as being the specialoriginal, or if the original is clearly seen as being not the specialoriginal, it can be accurately determined whether or not the original isthe special original or not. However, in a case of the original which ishardly seen as being the special original, such as a case of dirty papermoney or a sample of securities, the determination result depends on thereference similarity value set in the copy machine. For example, if thereference similarity value is high, an original which should bedetermined as being the special original is easily determined as notbeing the special original. Thus, a case where the special original isillegally copied may occur. On the other hand, if the referencesimilarity value is low, an original which should be determined as beingnot the special original is easily determined as being the specialoriginal. Thus, a case where a copy process for a normal original isprohibited may occurs. In this case, the efficient copy process isdeteriorated.

In addition, it has also been tried that input images are analyzed indetail and it is determined based on the analysis result whether or notan original corresponding to the input images is the special original.However, in this case, it takes a long time for the analysis of theinput images, so that a processing speed is deteriorated when a normaloriginal is copied.

DISCLOSURE OF THE INVENTION

Accordingly, a general object of the present invention is to provide acopying apparatus having a determination unit for the special originalin which apparatus the disadvantages described above are eliminated.

A more specific object of the present invention is to provide a copyingmachine in which a copy of a normal original can be carried out withouthindrance and having a determination unit for the special original whichunit prevents any special original from being copied without limitation.

The above objects of the present invention are achieved by a copyingapparatus comprising: image reading means for optically reading anoriginal and for outputting image signals corresponding to the original;image processing means for processing the image signals supplied fromthe image reading means in accordance with a predetermined method andfor outputting image data; image forming means for forming an imagecorresponding to the image data supplied from the image processing meanson a recording sheet; original determination means for determiningwhether a rank of certainty that the original is a predetermined specialoriginal is a first rank or a second rank lower than the first rank;prohibiting means for prohibiting the image corresponding to theoriginal from being formed on the recording sheet when the determinationresult obtained by the original determination means is the first rank;information adding means for adding predetermined information to therecording sheet on which the image is formed by the image forming meanswhen the determination result obtained by the original determinationmeans is the second rank.

According to the present invention, in a case where the rank ofcertainty that the original is the same as the special original such aspaper money is high (the first rank), the copy operation of the originalis prohibited. If an original having a low rank of certainty that theoriginal is the same as the special original is a normal original, animage forming operation is not prohibited and an image corresponding tothe original is formed on a recording sheet. In this case, although thepredetermined information is added to the recording sheet, there is nohindrance in the image forming process. On the other hand, even if anoriginal having a low rank of certainty that the original is the same asthe special original, since the predetermined information is added tothe recording sheet on which the image corresponding to the original isformed, the copying apparatus in which the special original such aspaper money was copied can be identified by the predeterminedinformation.

Additional objects, features and effects of the present invention willbecome apparent from the following detailed description when read inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating an example of a structure of a copyingapparatus according to the present invention.

FIG. 2 is a diagram illustrating a detailed structure of a marking unitprovided in the copying machine.

FIG. 3 is a diagram illustrating an example of arrangement of marksprinted on a recording paper.

FIG. 4 is a diagram illustrating an example of an ink roller having adivided structure.

FIG. 5 is a block diagram illustrating a control circuit of a copyingapparatus according to a first embodiment.

FIG. 6 is a diagram illustrating a constitution of an originaldetermination unit provided in the control circuit shown in FIG. 5.

FIG. 7 is a flow chart illustrating an operation of a determinationcircuit of the original determination unit.

FIG. 8 is a diagram illustrating feeding paths for recording papers in acopying apparatus according to a second embodiment.

FIG. 9 is a diagram illustrating a control circuit of the copyingapparatus according to the second embodiment.

FIG. 10 is a block diagram illustrating a constitution of an originaldetermination unit provided in the control circuit shown in FIG. 9.

FIG. 11 is a block diagram illustrating a control circuit of a copyingapparatus according to a third embodiment.

FIG. 12 is a flow chart illustrating a process of a system controllershown in FIG. 11.

FIG. 13 is a diagram illustrating a method of determining the specialoriginal.

FIG. 14 is a diagram illustrating another method of determining thespecial original.

FIG. 15 is a diagram illustrating another method of determining thespecial original.

FIG. 16 is a diagram illustrating another method of determining thespecial original.

FIG. 17 is a diagram illustrating another method of determining thespecial original.

FIG. 18 is a block diagram illustrating a modification of a seconddetermination system of the original determination unit of thecontroller shown in FIG. 11.

FIG. 19 is a flow chart illustrating an operation of the seconddetermination system shown in FIG. 18.

FIG. 20 is a diagram illustrating an example of chain coding.

BEST MODE FOR CARRYING OUT THE INVENTION

A description will now be given of embodiments of the present invention.

FIG. 1 shows a structure of a copying apparatus according to a firstembodiment of the present invention. Referring to FIG. 1, this copyingapparatus has an original setting base 101 on which an original is to beset, an optical scanning system 102, a laser writing unit 103, aphotosensitive drum 104, a charging unit 105 for uniformly charging thephotosensitive drum 104, a developing unit 106, a transfer drum 107, atransferring charger 108, a cleaning unit 109, a fixer unit 110, anejecting tray 111, a marking unit 112 and a paper supply unit 113. Theoptical scanning system 102 has an exposure lamp 102a, optically scansan original on the original setting base 101, and outputs image signalscorresponding to the original. The laser writing unit 103 emits a laserbeam modulated based on image data caused by the image signals from theoptical scanning system 102. The laser beam is project onto thephotosensitive drum 104 which has been uniformly charged. Due toprojecting the laser beam, an electrostatic latent image is formed onthe photosensitive drum 104. The developing unit 106 has four sectionsfor supplying to the photosensitive drum 104 yellow-toner (Y),magenta-toner (M), cyan-toner (C) and black toner (BK) respectively. Theelectrostatic latent image formed on the photosensitive drum 104 isdeveloped by the respective color toner. A recording paper ejected fromthe paper supply unit 113 is wound on the transfer drum 107, respectivecolor toner images are transferred to the recording paper by theoperation of the transferring charger 108 so as to be superposed on eachother. As a result, a multi-colored image is formed on the recordingpaper. The multi-colored image is fixed on the recording paper by thefixer unit 110. After passing through the fixer unit 110, the recordingpaper is ejected to the ejecting tray 111 via the marking unit 112.Toner remaining on the photosensitive drum 104 after the multi-coloredimage is transferred to the recording paper is removed from thephotosensitive drum 104 by the cleaning unit 109.

The marking unit 112 is formed, for example, as shown in FIG. 2.Referring to FIG. 2, the marking unit 112 has a marking roller 114, anink roller 115, an ink supplier 116 and a pressure roller 117. Themarking roller 114 is rotated with contacting the ink roller 115 towhich ink is supplied from the ink supplier 116. The type of ink is notlimited, but it is preferable that marks formed on a recording paper bythe ink are not easily erased therefrom. In addition, it is preferablethat ink having a loud color be used. In this case, a color of the inkmust be determined so that the quality of images formed on a surface ofthe recording paper is not affected by marks formed on the oppositesurface of the recording paper by the ink. Furthermore, special ink(made of indium-tin oxide, tin oxide or the like), such as ink having ahigh transmittance in a visible region and a low transmittance in aregion other than visible region, may be used. In this case, marksprinted by using the special ink are almost not visible normally, butthe marks can be made visible by irradiation of a light beam, such asultraviolet or infrared, other than the visible light.

The marking roller 114 and the pressure roller 117 are normallyseparated from each other. At starting of a marking operation, thepressure roller 117 and/or the marking roller are moved so as to beclose to each other. The pressure roller 117 presses the recording sheetagainst the marking roller 114 at a proper pressure so that a stablemarking operation can be carried out. A moving mechanism for thepressure roller 117 and/or the marking roller is not shown in thefigure, but can be easily formed by using known mechanisms. A pluralityof numeral sets are carved on the surface of the marking roller 114. Theink is uniformly applied to the surface of the marking roller 114 by theink roller 115, and marks formed of the respective numeral sets areprinted on the rear surface of the recording paper, as shown in FIG. 3.

The marks formed of the respective numeral sets represent informationidentifying the copying apparatus, such as a maker number, amanufacturing number or a customer management number. The plurality ofnumeral sets carved on the surface of the marking roller 114 arearranged so that, even if the special original assumed to be minimum isset at any position on the original setting base 101, at least one markis formed on the rear surface of a copy of the special original. Inaddition, the width of the marking roller 114 is determined based on themaximum width of the recording paper used in the copying apparatus.However, if the ink is applied to the whole surface of the markingroller 114 by the ink roller 115, the ink is transferred from themarking roller 114 to the pressure roller in a case where the recordingpaper having the width smaller than the maximum width is used. In thiscase, the surface of the recording sheet on which copied images areformed are brought into contact with the pressure roller, so that thesurface of the recording paper is soiled. Thus, in this embodiment, theink roller 115 is divided in accordance with the widths of the recordingpapers as shown in FIG. 4, and divided sections corresponding to thesize of the used recording paper are selectively used. The distancebetween divided sections of the ink roller 115 may not affect the marksformed on the surface of the marking roller 114, and the strict accuracyis not required for the distance between the divided sections. Inaddition, the marking roller 114 may be divided in the same manner asthe ink roller 115.

A control circuit of the copying apparatus as described above is formed.as shown in FIG. 5. Referring to FIG. 5, an image sensor (e.g. a CCDsensor) of the optical scanning system 102 outputs image signalscorresponding to a red color (R), a green color (G) and a blue color(B). The image signals are processed by a image processing unit 301 inaccordance with various algorithms, so that the image signals areconverted into image data items corresponding to a yellow color (Y), amagenta color (M), a cyan color (C) and a black color (BK). These imagedata items are supplied to the laser writing unit 103, so that the laserwriting unit 103 emits a laser beam modulated based on the respectiveimage data items. The image data obtained by digitizing the above imagesignals (R, G, B) is supplied from the image processing unit 301 to anoriginal determination unit 400. The original determination unit 400determines, based on the image data, whether or not the copyingoperation should be prohibited, or whether or not the marking unit 112should be activated. The operation/display unit 302 is used to inputvarious commands and to display various information items such asmessages. The optical scanning system 102, the image processing unit301, the laser writing unit 103, the original determination unit 400 andthe operation/display unit 302 are controlled by a system controller303.

The original determination unit 400 is formed as shown in FIG. 6.Referring to FIG. 6, the original determination unit 400 has an imagedetecting circuit 401, a memory 402, a comparing circuit 403, adetermination circuit 404, a copy operation control circuit 405 and amarking control circuit 406. The image detecting circuit 401 extractsdata (special data), corresponding to characteristic portions which havebeen previously determined on the special original such as the papermoney, from the image data. The memory 402 stores referencecharacteristic data identifying various special originals. The comparingcircuit 403 compares the characteristic data extracted by the imagedetecting circuit 401 with the reference characteristic data stored inthe memory 402, and outputs a similarity value obtained by evaluatingthe degree of similarity between both data. The determination circuit404 has a first reference similarity value and a second referencesimilarity value less than the first reference similarity value. Thedetermination circuit 404 then determines whether or not the similarityvalue output by the comparing circuit 403 is equal to or greater thanthe first reference similarity value and the second reference similarityvalue. The copy operation control circuit 405 activates either a copyprohibiting signal or a copy executing signal in accordance with thedetermination result obtained by the determination circuit 404. Inaddition, the marking control circuit 406 switches a marking signal froman active state to an inactive state and vice versa. The copyprohibiting signal and the copy executing signal are supplied to thesystem controller 303, the system controller 303 controls the operationof the copying apparatus in accordance with states of the copyprohibiting signal and the copy executing signal. The marking signal issupplied to the marking unit 112, and the marking unit 112 is activatedor inactivated in accordance with the state of the marking signal.

In the copying apparatus as described above, the following operation iscarried out.

Image data corresponding to a characteristic portion of the specialoriginal, such as a seal portion of the paper money, is extracted, andthe extracted image data is stored as the reference characteristic datain the memory 402. The special original includes Japanese paper moneyand securities and those in respective countries in the world. Thereference characteristic data corresponding to a special original isdetermined based on the analysis of image data for the correspondingspecial original.

Image data corresponding to a number portion, a signature portion or aportrait portion other than the image data corresponding to the seal maybe determined as the reference characteristic data.

When an operator sets an original on the original setting base 101 andcarries out a starting operation, the optical scanning system 102 scansthe original and image signals are output from the image sensor in theoptical scanning system 102. In the original determination unit 400,characteristic data is extracted from the image data corresponding tothe image signals by the image detecting circuit 401. The characteristicdata and the reference characteristic data stored in the memory 402 arethen compared with each other by the comparing circuit 403. In thecomparing circuit 403, for example, the characteristic data which hasbeen actually extracted is divided into pixels, the number of pixels andthe distribution state of pixels are respectively compared with those ofthe reference characteristic data, and a similarity value is calculatedbased on the comparison results in accordance with a predeterminedalgorithm. The similarity value is represented, for example, by apercentage. The greater the similarity value the more similar is theoriginal to the special original.

The determination circuit 404 carries out a determination process inaccordance with a flow chart shown in FIG. 7. That is, it is determinedwhether or not the similarity value obtained by the comparing circuit403 is equal to or greater than the first reference similarity value(e.g. 90%) (S501). If the similarity value is equal to or greater thanthe first reference similarity value (90%), the determination circuit404 outputs an agreement determining signal (S502). When the agreementdetermining signal is supplied to the copy operation control circuit 405and the marking control circuit 406, the copy operation control circuit405 activates the copy prohibiting signal (e.g. a high level) andinactivates the copy executing signal, and the marking control circuit406 maintains the marking signal in an inactive state. The systemcontroller 30 to which the copy prohibiting signal activated asdescribed above is input causes the operation of a printer system,including the image processing unit 301, the laser writing unit 103, thephotosensitive drum 104 and the developing unit 106, to stop. Aprohibiting message is then supplied from the system controller 30 tothe operation/display unit 302. As a result, the copy operation isstopped, and the prohibiting message, for example, "THIS ORIGINAL CANNOTBE COPIED: COPY PROHIBITED" is displayed on the operation/display unit302.

Returning to FIG. 7, if it is determined, in step S501, that thesimilarity value is less than the first reference similarity value(90%), it is further determined whether or not the similarity value isequal to or greater than the second reference similarity value (e.g.70%) (S503). If the similarity value is equal to or greater than thesecond reference similarity value (70%), the determination circuit 404outputs a similarity determination signal (S504). In this case, thesimilarity value x falls in a range of

    70%≦x<90%.

When the similarity determination signal is supplied to the copyoperation control circuit 405 and the marking control circuit 406, thecopy operation control circuit 405 inactivates the copy prohibitingsignal and activates the copy executing signal, and the marking controlcircuit 406 activates the marking signal. The system controller 30 towhich the copy executing signal activated as described above is inputsupplies a normal control signal to the printer system. As a result, amulti-colored image is formed, based on the image data (Y, M, C, BK)output from the image processing unit 301, on recording papers ejectedfrom the paper supply unit 113. In addition, in the marking unit 112 towhich the marking signal activated as described above is input, thepressure roller 117 is moved so as to be brought into contact with themarking roller 114, and the marking roller 114 is rotated. Thus, whenthe recording sheet on which the multi-colored image is formed passesthrough the marking unit 112, the marks are printed on the rear surfaceof the recording paper as shown in FIG. 3.

Returning to FIG. 7, if it is determined, in step S503, that thesimilarity value is less than the second reference similarity value(70%), the determination circuit 404 outputs a non-similaritydetermination signal (S505). When the non-similarity determinationsignal is supplied to the copy operation control circuit 405 and themarking control circuit 406, the copy operation control circuit 405inactivates the copy prohibiting signal and activates the copy executingsignal, and the marking control circuit 406 inactivates the markingsignal. As a result, in the marking unit 112, the pressure roller 117 isseparated from the marking roller 114 and the normal copy operation iscarried out.

As has been described above, according to the first embodiment, onlywhen it is securely determined that an original set on the copyingapparatus is the special original such as the paper money (thesimilarity value is equal to or greater than 90%), the copy operation isprohibited. Thus, even if a normal original is similar to the specialoriginal, the copy operation is not prevented. In addition, even if anoriginal which is determined as being similar to the special original isthe special original, the marks identifying the copying apparatus areprinted on the rear surface of the recording sheet. Thus, based on themarks painted on the paper money or the securities which have beenforged by illegal copy, at least a copying apparatus used for theillegal copy can be easily identified.

Furthermore, in a case where the copy operation is prohibited, theprohibiting message is displayed on the operation/display unit 302.Thus, the operator is not prevented from erroneously determining thatthe copying apparatus malfunctions.

A description will now be given of a second embodiment of the presentinvention.

In the second embodiment, the marks representing information identifyingthe copying apparatus are formed on the rear surface of a recordingpaper in accordance with an electrophotographic process using the laserwriting unit 103, the photosensitive drum 104, the charging unit 105,the developing unit 106 and other units, in the same manner as a copiedimage. Feeding paths for recording papers are formed, for example, asshown in FIG. 8. FIG. 8 mainly shows feeding paths for recording paperson which copied images are formed, and the copying machine in thisembodiment has approximately the same essential structure as that shownin FIG. 1. However, the copying machine according to the secondembodiment is not provided with the marking unit shown in FIG. 1.

Referring to FIG. 8, a switch-back path 602 and a switching nail 601 forselecting the switch-back path 602 or a path extending toward theejecting tray 111 are provided at the downstream side of the fixer unit110. In addition, a reversing path 603 connected to the switch-back path602 is smoothly connected to a paper supplying path extending from thepaper supply unit 113.

In addition, a control circuit of the copying apparatus is formed asshown in FIG. 9. That is, the control circuit is provided with a historyrecording unit 700 for recording a history regarding the copy operation.The original determination unit 400 is formed as shown in FIG. 10, andother units are the same as those shown in FIG. 5. Referring to FIG. 10,the original determination unit 400 has the image detecting circuit 401,the memory 402, the comparing circuit 403, the determination circuit 404and a copy operation control circuit 407 the image detecting circuit401, the memory 402, the comparing circuit 403 and the determinationcircuit 404 are the same as those shown in FIG. 6. The copy operationcontrol circuit 407 controls the states of the copy prohibiting signal,the copy executing signal and the marking signal based on thedetermination signals (the agreement determination signal, thesimilarity determination signal and the non-similarity determinationsignal) output from the determination circuit 404 in accordance with theflow chart shown in FIG. 7.

In the original determination unit 400 provided in the copying apparatusas described above, when the agreement determination signal is outputfrom the determination circuit 404 (the similarity value is equal to orgreater than 90%), the copy operation control circuit 407 activates thecopy prohibiting signal. As a result, the copy operation is prohibitedin the same manner as in the case of the first embodiment. At this time,the system controller 303 outputs history information regarding theprohibited copy operation, such as a date, a user ID, a type of detectedspecial original and a similarity value. The history information isrecorded in the history recording unit 700. In addition, when thenon-similarity signal is output from the determination circuit 404 (thesimilarity value is less than 70%), the copy operation control circuit407 activates the copy executing signal. As a result, the normal copyoperation is carried out, so that a multi-colored image corresponding toan original image is formed on a recording paper. The switching nail 601shown in FIG. 8 is switched so as to select the path extending towardthe ejecting tray 111, so that the recording paper passes through thefixer unit 110 and is ejected to the ejecting tray 111.

Furthermore, when the similarity determination signal is output from thedetermination circuit 404 (the similarity value is less than 90% and isequal to or greater than 70%), the copy operation control circuit 407activates the copy executing signal and the marking signal. As a result,the normal copy operation is carried out, so that a multi-colored imagecorresponding to the original image is formed on a recording paper.Further, the electrophotographic process in the normal copy operation iscompleted, image data corresponding to the marks shown in FIG. 3 isoutput from the image processing unit 301 based on an instruction fromthe system controller 303. Then, in a state where the section forsupplying the black toner (BK) is activated in the developing unit 106,the electrophotographic process is performed on the photosensitive drum104 again. At this time, the switching nail 602 shown in FIG. 8 isswitched so as to select the switch-back path 602, so that a recordingpaper obtained by the normal copy operation as described above passesthrough the fixer unit 110 and is then directed to the switch-back path602. When the recording paper is completely in the switch-back path 602,feed rollers are reversed so that the recording paper is directed fromthe switch-back path 602 to the reversing path 603. The recording paperfed in the reversing path 603 is reversed and directed to thephotosensitive drum 104. Black toner (BK) images of the marks are thenformed on the rear surface (opposite to the surface on which themulti-colored image is formed by the normal copy operation) of therecording paper. After this, the switching nail 601 shown in FIG. 8 isswitched so as to select the path extending toward the ejecting tray111, so that the recording paper passes through the fixer unit 110 againand is ejected to the ejecting tray 111. In this case, the historyinformation regarding the copy operation is recorded in the historyrecording unit 700 in the same manner as in a case where the copyoperation is prohibited.

In the second embodiment, the same effects as in the case of the firstembodiment are obtained. Furthermore, when the copy operation isprohibited and when the marks are printed on a recording paper, thehistory information regarding the copy operation is recorded in thehistory recording unit 700. Thus, a person which carried out the illegalcopy can be easily identified.

In the above first and second embodiments, in the case where the copyoperation is prohibited, the following process may be carried out.

First, a serviceman called by the user directly operates the systemboard so that a state of the system (in which the copy operation isprohibited) is reset. Second, information indicating that the illegalcopy was carried out is transmitted to a service station via a line.Then, a serviceman dispatched from the service station resets a state ofthe system as has been described above. Third, when the operator inputsa predetermined password number using numeral keys on theoperation/display unit 302 in a state where the history information isrecorded in the history recording unit 700, the copying apparatusreturns to a state where the copy operation can be carried out.

The marks representing the information identifying the copying apparatuscan be printed on the surface of the recording sheet on which surfacethe copied image is formed. In this case, in the marking unit 112, theink having a high transmittance to visible light and a low transmittanceto light other than the visible light is used. In addition, ink having acolor which is hardly seen by human eyesight, such as light yellow inkis used. Furthermore, in a case where the marks are formed, inaccordance with the electrophotographic process, on the surface of therecording paper on which surface a copied image is formed, the sectionfor supplying the yellow toner (Y) is activated in the developing unit105.

The structure of the marking unit 112 is not limited to that shown inFIG. 2, and, for example, a known ink jet recording unit can be used asthe marking unit 112.

A description will now be given of a third embodiment of the presentinvention.

In the third embodiment, the copying apparatus has the same structure asthat shown in FIG. 1. In addition, the control circuit is formed asshown in FIG. 11.

Referring to FIG. 11, detecting signals from an image sensor 201provided in the optical scanning system are converted into digital imagesignals (RGB signals) by an A/D converter 202 operated in synchronismwith a clock signal from a clock generator 190. The RGB signals aresupplied to the image processing unit 301. The image processing unit 301has a color-correction/color-processing circuit 203, a selector 204 anda memory 205. The color-correction/color-processing circuit 203 receivesthe RGB signals and carries out the color correction and the colorprocessing. The selector 204 successively selects one of color imagesignals corresponding to cyan (C), magenta (M), yellow (Y) and black(BK) output from the color-correction/color-processing circuit 203. Acolor image signal output from the selector 204 is temporarily stored inthe memory 205. A driving circuit 103a drives a laser diode 103b basedon the color image signals from the image processing unit 301. Inaddition, the RGB signals from the A/D converter 202 are also suppliedto the original determination unit 400. This control circuit further hasa control data buffer 214 for storing determination results obtained bythe original determination unit 400, a ROM 215, a RAM 216 and an IPU-CPU217 (a CPU for image processing), and is connected to the systemcontroller 303 via a communication interface 218.

The original determination unit 400 has a first determination system anda second determination system. The first determination system is formedof an extracting circuit 207, a first specific pattern memory 209(formed of an EEPROM or a non-volatile RAM) and a first detectingcircuit 208. The extracting circuit 207 extracts a specific pattern fromRGB signals supplied in reading operation for an original. A referencepattern identifying the special original such as the paper money isstored in the first specific pattern memory 209. The first detectingcircuit 208 determines whether or not the specific pattern extracted bythe extracting circuit 207 is matched to the reference pattern stored inthe first specific pattern memory 209. That is, in the firstdetermination system, it is determined, in synchronism with the readingoperation for the original, whether or not the original is the specialoriginal. Since the process is carried out in synchronism with thereading operation for the original, a determination result can berapidly obtained in the first determination system. The seconddetermination system has an image signal memory 210, a combining circuit211, a second specific pattern memory 213 (formed of an EEPROM or anon-volatile RAM) and a second detecting circuit 212. The image signalmemory 210 divides the RGB signals supplied in the reading operation forthe original into an R-signal, a G-signal and a B-signal and storesthese signals. The combining circuit 211 processes the R-signal, theG-signal and the B-signal read out from the image signal memory 210 inaccordance with a predetermined algorithm, and outputs a specificpattern obtained by selectively combining processed signals. The secondspecific pattern memory 213 stores a reference pattern identifying thespecial original. The second detecting circuit 212 determines whether ornot the specific pattern from the combining circuit 211 is matched tothe reference pattern stored in the second specific pattern memory 211.That is, in the second determination system, the RGB signals for onepage obtained by the reading operation for the original are stored inthe image signal memory 210. After the reading operation for theoriginal is completed, it is determined, based on the RGB signals (theimage signals) stored in the image signal memory 210, whether or not theoriginal is the special original. Since the specific pattern of theoriginal is made based on the image signals for one page stored in theimage signal memory 210, a time required in the second determinationsystem is longer than a time required in the first determination system.However, the determination accuracy obtained in the second determinationsystem is superior to the determination accuracy obtained in the firstdetermination system.

The determination results obtained by the first and second determinationsystems are stored in the control data buffer 214. The determinationresults are supplied from the control data buffer 214 to the systemcontroller 303 via the data bus and the communication interface 218 inresponse to the request from the system controller 303.

When an image forming process is carried out, system controller 303carries out a process in accordance with a flow chart shown in FIG. 12.

When a start operation is performed in a state where an original is seton the original setting base 101, the system controller 303 supplies anactivating signal to the optical scanning system (S601). Thus, theoptical scanning system scans the original, and RGB signals depending ondetecting signals output from the image sensor 201 are supplied to theimage processing unit 301 and the original determination unit 400. Whilethe original is being read, in the image processing unit 301, colorimage signals (C, M, Y, BK) are stored in the memory 205. In addition,in the first determination system of the original determination unit 400(the extracting circuit 207, the first detecting circuit 208 and thefirst specific pattern memory 209), a determination process is carriedout. In the second determination system (the image signal memory 210,the combining circuit 211, the second detecting circuit 212 and thesecond specific pattern memory 213), the RGB signals are successivelystored in the image signal memory 210. While the above process is beingcarried out, the system controller 303 determines whether or not thereading operation is completed (S602). When the reading operation forthe original by the optical scanning system is completed, a terminatingsignal is supplied from the optical scanning system to the systemcontroller 303, so that the system controller determines, based on theterminating signal, whether the reading operation for the original hasbeen completed. At this time, the process in the first determinationsystem of the original determination unit 301 is also completed, thedetermination result (a first determination result) is stored in thecontrol data buffer 214. The system controller 303 reads out thedetermination result from the control data buffer 214. If it isdetermined, based on the determination result, that the original is notthe special original such as the paper money (S603), the systemcontroller 303 supplies a control signal for starting of the imageprocessing to the image processing unit 301 and the printer system shownin FIG. 1 (S604). As a result, the image signals stored in the memory205 in the image processing unit 301 are supplied to the laser writingunit, and a multi-colored image corresponding to the original is formedon a recording paper.

On the other hand, when the system controller 303 detects, based on thedetermination result (the first determination result), that the originalis the special original (S603), the original determination unit 400 isinstructed that the second determination process is carried out (S605).In response to receiving the instruction, in the second determinationsystem of the original determination unit 400, it is determined whetheror not a specific pattern of the original obtained from the RGB signalsstored in the memory 210 is matched to the reference pattern. Thedetermination result (the second determination result) is then stored inthe control data buffer 214. After this, the system controller 303 readsout the second determination result from the control data buffer 214.When it is determined, based on the determination result, that theoriginal is the special original (S606), the system controller 303supplies an instruction for prohibiting the image forming process to theimage processing unit 301 and the printer system (S607). As a result,the image signals stored in the memory 205 of the image processing unit301 is cleared and the printer system is not activated. At this time,the message representing that the image forming processing has beenprohibited is displayed on the operation/display unit, in the samemanner as in the first embodiment. On the other hand, when it isdetermined, based on the second determination result, that the originaldiffers from the special original (S606), the system controller 303supplies a starting instruction for the image forming process to theprinter system (S608) and supplies an activation signal to the markingunit 112 (S609). As a result, in the same manner as in .the firstembodiment, a multicolored image corresponding to the original is formedon a recording paper and marks identifying the copying apparatus areformed on the rear surface of the recording paper as shown in FIG. 3.

According to the third embodiment described above, in a case where onlythe first determination system determines that the original is thespecial original, the rank of certainty to the determination result willbe low. In this case, the image forming process is not prohibited andthe marks identifying the copying apparatus are formed on the rearsurface of the recording paper on which the multi-colored image isformed. In addition, in a case where both the first and seconddetermination systems determine that the original is the specialoriginal, the rank of certainty to the determination will be high. Inthis case, the image forming process is prohibited. Thus, an originalwhich is clearly seen as not being the special original is applied toonly the first determination system. An original which is doubtful to bethe special original and an original which is clearly seen to be thespecial original, that is, only originals which are determined as beingthe special original by the first determination system are applied tothe second determination system. As a result, the copy operation for thenormal originals can be performed without hindrance.

The processes in the first and second determination systems are notlimited to those in the above embodiments, but the following processesmay be performed therein.

FIG. 13 shows a determination system using magnetic information of thespecial original. Referring to FIG. 13, a magnetism generating unit 801and a magnetism detecting unit 802 are located under a contact glass804. When a special original 805 such as paper money using magnetic inkis set on the contact glass 804, a magnetic field generated by themagnetism generating unit 801 is directed to the magnetism detectingunit 802 by the magnetic ink of the special original 805. As a result,the magnetism detecting unit 802 detects the magnetic field, and a CPU803 determines, based on the detecting result, whether or not theoriginal is the special original 805.

FIG. 14 shows a determination system which determines, using the shapeof an original, whether or not the original is the special original.Referring to FIG. 14, coordinates (x1, y1), (x2, y2), (x3, y3) and (x4,y4) corresponding to corners of the special original 901 set on acontact glass 903 are calculated based on image information obtained bythe optical scanning system. A shape of the original is detected basedon the respective coordinates. It is then determined, based on thedetecting result, whether or not the original is the special original901.

FIG. 15 shows a method for determining, based on the color histogram ofa background of an original, whether or not the original is the specialoriginal. In this method, a background color of the original isextracted. The color histogram (R, G, B) of the extracted backgroundcolor of the original as shown in FIG. 15(a) and a reference colorhistogram, as shown in FIG. 15(b) which is registered in a memory arecompared with each other. It is determined, based on the comparonresult, whether of not the original is the special original.

FIG. 16 is a method for determining, using a specific pattern of thespecial original, whether or not an original is the special original. Inthis method, a specific pattern (the whole special original or a part ofthe special original), such as a seal portion of the paper money, isextracted from the special original. The extracted specific pattern anda reference pattern which is registered in a memory are compared witheach other. It is then determined, based on the comparing result,whether or not the original is the special original.

FIG. 17 shows a method for determining, based on the color histogram ofan original, whether or not the original is the special original. Inthis method, the hue of the original is extracted. The color histogram(R,G, B) of a part or the whole of the original from which the hue isextracted is compared with the reference color histogram registered in amemory. It is then determined, based on the comparing result, whether ornot the original is the special original.

A further description will now be given of an example in which imagedata is coded into chain codes.

A control circuit shown in FIG. 18 has the optical scanning system 102,the image processing unit 301, the laser writing unit 103, the firstdetermination system 400a and the second determination system, in thesame manner as in the third embodiment. In the second determinationsystem 400b, the image data is coded into chain codes. The seconddetermination system 400b is provided with memories 415R, 415G and 415B,vector number operating circuits 416R, 416G and 416B, comparing circuits418R, 418G and 418B, a reference data memory 417 and an AND circuit 419.Image data: R-data (red), G-data (green) and B-data (blue) aretemporarily stored in the memories 415R, 415G and 415B respectively. Thevector number operating circuits 416R, 416G and 416B are respectivelyconnected to the memories 415R, 415G and 415B, and the comparingcircuits 418R, 418G and 418B are respectively connected to the vectornumber operating circuits 416R, 416G and 416B. Each of the vector numberoperating circuits 416R, 416G and 416B codes R-data, G-data or B datafrom a corresponding one of the memories 415R, 415G and 415B into chaincodes so that the vectorization of the data is performed. Vector numbersin respective directions are then calculated. The reference data memory417 is provided with vector numbers which have been previouslycalculated for the special original in the respective directions. Eachof the comparing circuits 418R, 418G and 418B compares the vectornumbers calculated by a corresponding one of the vector number operatingcircuits 416R, 416G and 416B with the reference vector numbers stored inthe reference data memory 417. Each of the comparing circuits 418R, 418Gand 418B outputs a determination signal based on the comparing result.The AND circuit 419 to which the determination signals are supplied fromthe comparing circuits 418R, 418G and 418B outputs a seconddetermination signal representing whether or not the original is thespecial original.

In the second determination system 400b described above, a process iscarried out in accordance with a flow chart shown in FIG. 19.

First, the R-data, G-data and B-data obtained by the optical scanningsystem 102 are respectively input to the memories 415R, 415G and 415B(S201, S218 and S232). Next, in the vector number operating circuits416R, 416G and 416B, the outline of a line figure (image data) is codedinto chain codes (S202, S219 and S233), so that the image data isclassified into eight codes "0"-"7" shown in FIG. 20. FIG. 20illustrates a chain coding method which is generally known. In thischain coding method, a line figure is represented by connection ofvectors having a length of a or √2a and eight directions, where arepresents a length of a side of a quantizing lattice. That is, codes"0"-"7" are assigned to the line figure in accordance with thedirections of the vectors. According to this chain coding method, theline figure is converted into eight codes depending on the directions,and the number of codes is counted.

In a case of the special original, the distribution of numbers of codesin accordance with characteristics of an image is uniform. Thus, withreference to the distribution of the numbers of codes, an angle at whichthe special original is set on the copy apparatus can be determined.Actually, the angle of the special original can be determined withreference to only the maximum number of codes (S204, S221 and S234).

The number of codes obtained by chain coding of the special original iscounted for each vector, and the vector number is stored as thereference vector number in the reference data memory 417, as has beendescribed above. In the comparing circuits 418R, 418G and 418B, thereference vector number in the reference data memory 417 and the vectornumber of the input image data are compared code by code. If thecomparing result is equal to or greater than a predetermined level (forexample, the conformity rate in each code is equal to or greater than90%), it is determined that the original is the special original. Thus,in the process to this point, the determination results are obtained,based on the R-data, G-data and B-data, from the respective comparingcircuits 418R, 418G and 418B (S205-S214, S222-S231 and S2356-S245).

The AND circuit 419 receives the determination results from therespective comparing circuits 418R, 418G and 418B. When all thedetermination results represent that the original is the specialoriginal, the AND circuit 419 turns on the second determination signal(S215 and S216). In other cases, the second determination signal isturned off (S215 and S217). The system controller 303 then controls theprinter system and the marking unit 112 in accordance with the state ofthe second determination signal as described in the third embodiment.

As has been described above, the image data can be represented byvectors in accordance with the chain coding method, the processing speedcan be improved.

The present invention is not limited to the aforementioned embodiments,and variations and modifications may be made within the scope of theclaimed invention.

POSSIBILITY OF APPLYING TO INDUSTRY

According to the present invention, only when the rank of certainty thatthe original is the special original is high, the copying operation isprohibited. In a case where the certainty is in a low rank,predetermined information is added to the recording paper. Thus, thecopying operation for a normal original can be carried out withouthindrance, and at least the predetermined information is added to thecopy of the special original so that the copying apparatus in which theillegal copy of the special original was carried out can be identifiedbased on the predetermined information.

We claim:
 1. A copying apparatus comprising:image reading means foroptically reading an original and for outputting image signalscorresponding to the original; image processing means for processing theimage signals supplied from said image reading means in accordance witha predetermined method and for outputting image data; image formingmeans for forming an image corresponding to the image data supplied fromsaid image processing means on a recording sheet; original determinationmeans for determining whether a rank of certainty that the original is apredetermined special original is a first rank or a second rank lowerthan the first rank; prohibiting means for prohibiting the imagecorresponding to the original from being formed on the recording sheetwhen the determination result obtained by said original determinationmeans is the first rank; information adding means for addingpredetermined information to the recording sheet on which the image isformed by said image forming means when the determination resultobtained by said original determination means is the second rank.
 2. Thecopying apparatus as claimed in claim 1, wherein said originaldetermination means comprises:storage means for storing reference datarepresenting a characteristic of the predetermined special original;characteristic extracting means for generating, based on the imagesignals from said image reading means, characteristic data representinga characteristic of the original; comparing means for comparing thecharacteristic data generated by said characteristic extracting meansand the reference data in said storage means with each other and forgenerating a similarity value representing a degree of similaritybetween the characteristic data and the reference data; firstdetermination means for determining whether or not the similarity valuefrom said comparing means is equal to or greater than a first referencesimilarity value; and second determination means for determining whetheror not the similarity value from said comparing means is equal to orgreater than a second reference similarity value less than the firstreference similarity value, wherein when said first determination meansdetermines that the similarity value is equal to or greater than thefirst reference similarity value, said original determination meansdetermines that the rank of certainty is the first rank, when said firstdetermination means determines that the similarity value is less thanthe first reference similarity value and when the second determinationmeans determines that the similarity value is equal to or greater thanthe second reference similarity value, the original determination meansdetermines that the rank of certainty is the first rank.
 3. The copyingapparatus as claimed in claim 1, wherein said original determinationmeans comprises:first determination means for determining, in accordancewith a first method, whether or not the original read by said imagereading means is the same as the predetermined special original; andsecond determination means for determining in accordance with a secondmethod, whether or not the original read by said image reading means isthe same as the predetermined special original, when both said first andsecond determination means determines that the original is the same asthe predetermined special original, said original determination meansdetermines that the rank of certainty is the first rank, when said firstdetermination means determines that the original is the same as thespecial original and when said second determination means determinesthat the original is not the same as the special original, said originaldetermination means determines that the rank of certainty is the secondrank.
 4. The copying apparatus as claimed in claim 1, wherein theinformation to be added to the recording sheet by said informationadding means is a mark representing information identifying said copyingapparatus.
 5. The copying apparatus as claimed in claim 1, wherein theinformation to be added to the recording sheet by said informationadding means is formed of a plurality of marks, said plurality of marksbeing arranged so that at least one mark is located in an areacorresponding to a minimum sized special original on the recordingsheet.
 6. The copying apparatus as claimed in claim 1 furthercomprising:display means for displaying a message indicating that theimage forming is prohibited when said prohibiting means prohibits theimage from being formed.
 7. The copying apparatus as claimed in claim 1further comprising:history recording means for, when said determinationmeans determines that the rank of certainty is either the first rank orthe second rank, recording information regarding an image formingprocess corresponding to the determination result.
 8. The copyingapparatus as claimed in claim 3, wherein a determination process in saidfirst determination means is carried out prior to a determinationprocess in said second determination means.
 9. The copying apparatus asclaimed in claim 8, wherein the first method and the second method aredecided so that a time required for the determination process in saidfirst determination means is shorter than a time required for thedetermination process in said second determination means.
 10. Thecopying apparatus as claimed in claim 8, wherein a determinationaccuracy of said second determination means is higher than adetermination accuracy of said first determination means.